Tesco, the UK’s biggest supermarket chain and Booker, the UK’s largest food wholesaler asked the competition regulator to fast-track its probe into their planned £3.5bn merger.

The regulator will make a judgement on whether consumers will have less choice as a result of the tie-up.

In late May, the Competition and Markets Authority (CMA) started an initial review into one of the most ambitious merger proposals in the food and drink industry.

The CMA said it would reach a decision on whether to launch a full investigation by 25 July.

Interested parties were invited to submit comments in early June.

However both Tesco and Booker requested that the CMA immediately proceed directly to a full inquiry, which takes 24 weeks.

“We have now requested that the CMA uses the ‘fast track’ process to allow it to move more quickly to examining the merger through a detailed phase 2 process,” the companies said in a joint statement on Thursday.

The CMA has ten working days to decide whether to accept or refuse the request.

The fast-track process has been used in past merger investigations, including the tie-up between BT and EE last year.

If the merger is approved, the combined companies will amass a revenue of more than £60bn and Tesco will see its market share increase to above 30 percent.

Tesco could be forced to get rid of more than 600 stores, many of which are situated less than 500 metres from a shop in Booker’s network of Premier, Londis and Budgens stores, according to analysis by the data team at The Times.

Schroders, one of Tesco’s biggest shareholders, told the BBC that it had “major concerns” about the deal in March.